The effect of urea-to-nitrates ratio on the morphology and magnetic properties of Mn0.8Mg0.2Fe2O4 (original) (raw)
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International Journal of Nanoparticles, 2016
Nanoferrite powders having composition Mn x Mg 1-x Fe 2 O 4 (x = 0.0, 0.2, 0.4, 0.6, 0.8) were synthesised by the chemical co-precipitation method and then sintered as the pellets. The X-ray diffraction (XRD), Alternating Gradient Force Magnetometer (AGFM) techniques and Curie temperature measurement were used to carry out this study. The XRD patterns confirm the nanosized dimension of the samples and showed that the samples are single phase cubic spinel nanoferrites. From the analysis of XRD data using Scherrer's formula, the average crystallite size (D XRD) of the particles was found to decrease from 81 to 55 nm with increasing manganese substitution. Substitution of Mn 2+ in MgFe 2 O 4 causes an increase in the lattice constant (a) from 8.35 to 8.43 Å. The magnetic parameters such as saturation magnetisation (M S), coercivity (H C) and remanence (M r) with increasing Mn 2+ concentration are studied at room temperature by an AGFM. Substitution of Mn 2+ for Mg 2+ increased M S from 21.2 to 74.7 emu g-1 and decreased H C from 23 to 10 Oe and decreased Curie temperature from 392 to 294°C.
Journal of physics, 2018
The magnetic material of Manganese Ferrite (MnFe2O4) based on natural Iron sand have been successfully prepared by using co-precipitation method. The natural Iron sand, MnCl2.4H2O, HCl and NH4OH were used as raw materials to synthesize the MnFe2O4. The synthesis was carried out at various temperatures of 70, 100 and 130°C, respectively. The physical and the magnetic properties of the samples were analysed by using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The diffraction pattern indicates that the MnFe2O4 is the dominant phase. The crystallite size tends to increase as the synthesis temperature increased while the saturation magnetization of MnFe2O4 tends to decrease.
Physica B: Physics of Condensed Matter, 2022
Al doped Mn ferrite, MnAlxFe2-xO4 (x = 0.1, 0.2, & 0.3), nanoparticles were synthsized by facile and simple solution combustion route. Effect of Al3+ ions substitution on the structural, optical, electrical and magnetic properties were explored. X-Ray diffraction (XRD) results confirm the formation of pure cubic phase for all the synthesized nanoparticles having spinel structure. Various structural parameters like crystallite size, lattice parameter, site radii and bond lengths were estimated from XRD data. For the strain analysis and consideration of contribution of every peak in XRD data, W-H and N-R plots were analysed. Scannining electron microscopy (SEM) revealed the compact surface morphology with grain size in nano meter range. FTIR spectra confirmed the presence of metal stretching vibrations at tetrahedral and octahedral sites for all MnAlxFe2-xO4 nanoparticle compositions, which is typical of spinel ferrites with FCC structure. Raman spectroscopy helped in analysing metal stretching vibrations of the synthesized samples and obtained raman modes were found to be as predicted by group theory. Dielectric constant decreases with increase in frequency reflecting the normal behaviour of the ferrites. Dielectric loss also followed the same trend. Both the behaviours have been explained in view of Koop ׳s theory and Maxwell–Wagner polarization-model. The synthesized ferrite samples exhibited the soft magnetic nature as confirmed by vibrating sample magnetometer. The room temperature hysteresis curves indicate the decrease in saturation magnetization as well as retentivity with the increase in Al3+ ions doping. The decrease in magnetic moment values have been explained on the basis of cation preference for the sites and also on weakening of exchange interaction upon aluminium doping.
Influence of temperature on structural and magnetic properties of Co0⋅5Mn0⋅5Fe2O4 ferrites
Co 0⋅5 Mn 0⋅5 Fe 2 O 4 ferrites have been synthesized using a single-step sol-gel auto-combustion method in which the metal nitrate (MN)-to-citric acid (CA) ratio was adjusted to 0⋅5 : 1 and pH to 7, respectively. The structural and magnetic properties of as-burnt and annealed samples were studied as a function of temperature. The inverse spinel structure was confirmed by X-ray diffraction (XRD) and crystallite size was estimated by the most intense peak (311) using Scherrer's formula. Contrary to earlier studies reported in the literature, both as-burnt and annealed samples exhibit crystalline behaviour. Room temperature magnetic properties were studied using vibrating sample magnetometer (VSM) with field strengths up to ± 10 kOe. Lattice constant and crystallite size increased as the annealing temperature was increased. However, the coercivity (H c ) initially increased and then decreased with the increase of crystallite size. The variation in coercivity is ascribed to the transition from a multi-domain to a single-domain configuration. Figure 6. Variation of coercivity with annealing temperature.
Ni 0.1 Mn 0.4 Cu 0.2 Cd 0.3 Fe 2 O 4 nanoparticles have been synthesized by following the sol-gel auto combustion process. Crystallite size and lattice constants have been calculated from XRD data. It has been observed that the experimental lattice constant value was estimated 8.466 Å, while the theoretical lattice constant value was estimated 8.342 Å. Surface morphology has been examined by TEM and FESEM micrographs. The average particle size has been derived from the histogram drawn from the FESEM image was found 42.5 nm. The presence of all elements has been confirmed by the EDS spectrum. From the two distinguished absorption bands noticed from the FT-IR spectrum, the formation of spinel ferrites has been confirmed. Intrinsic magnetization has been observed from the VSM data. Using VSM data, various parameters that are related to magnetization have been determined.
Preparation of Ni1−xMnxFe2O4 ferrites by sol–gel method and study of their cation distribution
Ceramics International, 2013
The nanoparticles of the spinel ferrite system Ni 1-x Mn x Fe 2 O 4 with x=0.0, 0.1, 0.3, 0.5, 0.7 and 0.9 were prepared by sol-gel combustion technique using chlorides of Ni, Mn and Fe with citric acid as a source. The structure of ferrite materials and the particle size were determined by x-ray diffraction (XRD). It was observed that the structure is single phase, face centered cubic with lattice parameters and the particle size ranging from 8.365Ǻ to 8.394Ǻ and 23.86Ǻ to 38.30Ǻ respectively. The lattice parameter showed a linear dependence on concentration in accordance with the Vegard's law. By analyzing XRD patterns, the cation distribution over A and B-sites was estimated through R-Factor method. The magnetic moment for each sample was determined from cation distribution on the two sites. An enhancement in the net magnetic moment was observed with gradual increase in the Mn content.
Journal of Physics: Conference Series, 2018
The magnetic material of Manganese Ferrite (MnFe2O4) based on natural Iron sand have been successfully prepared by using co-precipitation method. The natural Iron sand, MnCl2.4H2O, HCl and NH4OH were used as raw materials to synthesize the MnFe2O4. The synthesis was carried out at various temperatures of 70, 100 and 130°C, respectively. The physical and the magnetic properties of the samples were analysed by using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The diffraction pattern indicates that the MnFe2O4 is the dominant phase. The crystallite size tends to increase as the synthesis temperature increased while the saturation magnetization of MnFe2O4 tends to decrease.
In this study, 0.15, 0.25, 0.35, 0.5) ferrite nanoparticles were prepared by sol-gel autocombustion method. Structural, magnetic and morphology properties of obtained nanoparticles were investigated with Xray Diffraction (XRD), Vibrating Sample Magnetometer (VSM) and Transmission Electron Microscopy(TEM), respectively. The XRD results show that the most dominant peaks for samples is related to the Spinel phase. Crystalline size using Scherrer's equation for different values of x were obtained between 44 to 64 nm. VSM results showed that the saturation magnetization and coercivity values changed with increasing Mn. TEM images obtained results are in good agreement with the XRD results.
Journal of Superconductivity and Novel Magnetism, 2018
Detailed investigations of the microstructural, magnetic, magnetocaloric, and electrical properties of Ni 0.4 Mg 0.3 Cu 0.3 Fe 2 O 4 ferrite synthesized by sol-gel method have been investigated. XRD pattern indicates that sample has cubic spinel structure with F d3m symmetry. The cation distribution of the sample has been determined by Rietveld refinement. Temperature dependence of magnetization shows that sample exhibits a second-order PM to FM phase transition at the Curie temperature T C = 690 K. From the M(μ 0 H, T) data, we found that the maximum entropy change S max M reaches value of about 1.56 J kg −1 K −1 and relative cooling power (RCP) of 136 J kg −1 at μ 0 H = 5 T. From electrical conductivity curves, the estimated value of the activation energy is equal to 0.349 eV. The Nequist diagram at different temperatures reveals that the grain boundary contribution is responsible to the conduction process for the studied sample.